Post navigation

Band Around The World

Band Around The World

Please wait while the activity loads. If this activity does not load, try refreshing your browser. Also, this page requires javascript. Please visit using a browser with javascript enabled.

If loading fails, click here to try again

Question 1

Earth's circumference is 24,901 miles (40,075 km). Imagine it's as smooth as a cue ball, or even smoother like a neutron star. Imagine there's a stiff tight band around it. Now if 10 feet (3 meters) is added to the band raising it up above the ground equally around the whole world could you:

A

Barely slip a piece of paper under it.

B

Crawl under it.

C

Walk under it.

Question 1 Explanation:

The question is really asking about the increase in radius of a circle. The circumference is equal to:
C = 2R * π
But we want to know how much higher this band is which is really asking what's the increase in radius. Rearranging the formula to find R:
R = C / (2 * π)
Let's just calculate how much radius increases with 10 feet:
R = 10 / 6.28 = 1.59'
About two feet, enough to shimmy under.

There is 1 question to complete.

Return

Shaded items are complete.

1

Return

You have completed

questions

question

Your score is

Correct

Wrong

Partial-Credit

You have not finished your quiz. If you leave this page, your progress will be lost.

Correct Answer

You Selected

Not Attempted

Final Score on Quiz

Attempted Questions Correct

Attempted Questions Wrong

Questions Not Attempted

Total Questions on Quiz

Question Details

Results

Date

Score

Hint

Time allowed

minutes

seconds

Time used

Answer Choice(s) Selected

Question Text

All done

Need more practice!

Keep trying!

Not bad!

Good work!

Perfect!

I saw this question in an old time book by Lillian and Hugh Lieber, probably titled Infinity. It is wonderfully counter-intuitive and points out the need to really think and analyze problems.